Field of the Invention
The present invention relates to an electronic device which passes therethrough electric signals in a predetermined frequency band and blocks electric signals in other frequency bands.
Related Background Art
As a circuit for use in a high-frequency band, one equipped with a coupler has conventionally been known. For example, Patent Literature 1 discloses an amplifier with low third intermodulation equipped with a coupler. This amplifier with low third intermodulation causes two signal paths to produce third intermodulation with the same amplitude in antiphase with each other and combines two signals transmitted through the respective signal paths at the coupler in antiphase, so as to reduce the third intermodulations.
Patent literature 1: Japanese Patent Application Laid-Open No. H05-206743
Meanwhile, a filter made of a microstrip line comprising a plurality of conductor patterns arranged at predetermined intervals in a predetermined direction has been known as an electronic device for use in a high-frequency band. Such a microstrip line filter has a relatively large size. The microstrip line filter also requires a high precision for the conductor patterns.
It is therefore an object of the present invention to provide an electronic device which is small in size and requires less precision in conductor patterns.